Eccentric and means for adjusting the eccentricity thereof



April 2, 1968 R. VOELLER 3,375,732

ECCENTRIC AND MEANS FOR ADJUSTING THE ECCENTRICI'I'Y THEREOF Filed May 11, 1966 2 Sheets-Sheet 1 INVENTOR ROLF VOELLER BY ,9 M4 I a M/l finke/ ATTQRNEY April 2, 8 I R. VOELLER 3,375,732

ECCENTRIC AND MEANS FOR ADJUSTING THE ECCENTRICITY THEREOF Filed May 11. 1966 2 Sheets-Shee t INVENTOR ROLF VOE LL ER 'Ja a! 0 Mia ATTORNEY United States Patent 3,375,732 ECCENTRIC AND MEANS FOR ADJUSTING THE ECCENTRICITY THEREOF K Rolf Voeller, Dagersheim, Germany, assignor to Fortuna- Werke, Spezialmaschinfabrik Aktiengesellschaft, Stuttgart-Bad Cannstatt, Germany Filed May 11, 1966, Ser. No. 549,393 8 Claims. (Cl. 74571) The present invention relates to an eccentric and means for adjusting the eccentricity thereof. More specifically, the present invention relates to an eccentric comprising a shaft having a cylindrical portion fixed to the shaft eccentrically arranged with respect to the shaft axis and a sleeve surrounding the eccentrically arranged portion of the shaft and having an outer cylindrical surface and a bore having an inner cylindrical surface of a diameter substantially equal to that of the cylindrical eccentric portion of the shaft and engaging the latter, the bore is eccentrically arranged with respect to the outer cylindrical surface of the sleeve and one of the parts of the eccentric can be held during adjustment of the eccentricity thereof with respect to the other part whereas after adjusting the eccentricity the parts are secured to each other against relative movement.

The exact adjustability of the eccentricity of an eccentric v is essential for the exact grinding of exchangeable polygon profiles on polygon grinding machines in which the grinding wheel is guided along an ellipse the small horizontal axis of which is equal to double the value and the large vertical axis of which is equal n 2 the value of the eccentricity of the eccentric whereby n is equal to the number of the corners of the profile. With the means so far known in the art it was only possible to adjust the eccentricity with an adjusting tolerance of 0.1 mm., which is not sufficient for the exact grinding of exchangeable polygon profiles in which an adjusting tolerance of the eccentric of 0.01 mm. is necessary, which, however, has not been obtainable with the means so far known in the art.

It is an object of the present invention to provide for an eccentric and means for adjusting the eccentricity thereof in a much more exact manner as has been possible with the arrangements known in the art.

It is an additional object of the present invention to provide an eccentric and means for adjusting the eccentricity thereof which is composed of relatively few parts so that the whole arrangement can be manufactured at reasonable cost and will stand up perfectly under extended USE.

With these objects in view, the eccentric and means for adjusting the eccentricity thereof according to the present invention mainly comprises a shaft having an axis and a cylindrical portion fixed to the shaft and eccentrically arranged with regard to the shaft axis, a sleeve surrounding said eccentrically arranged portion on the shaft and having an outer cylindrical surface and a bore having an inner cylindrical surface of a diameter substantially equal to that of the cylindrical eccentric portion of said shaft and engaging the latter, wherein the bore is eccentrically arranged with respect to the outer cylindrical surface of the sleeve and the sleeve is formed at an end face thereof with a radial groove. The arrangement includes further mounting means mounting the shaft turnable about its axis, releasable coupling means for releasably connecting the sleeve and the shaft to each other, and axially movable arresting pin carried by the mounting means and having a free end adapted to engage in the aforementioned groove to prevent the sleeve to turn about the axis of its cylindrical outer surface while permitting the sleeve to move in direction transverse to the axis thereof and to tilt about the axis of the pin, whereby when the coupling means is released and the pin engaged in the groove the eccentricity of the eccentric may be adjusted by turning the shaft about its axis.

The radial groove in the end face of the sleeve is thereby located along a line passing through the intersection points of a plane normal to the axis of the shaft with the axis of the bore and the axis of the outer cylindrical surface of the sleeve and the groove being spaced further from the first mentioned intersection point than from the second mentioned intersection point. Since the axis of the arresting pin remains stationary and at a fixed distance from the turning axis of the shaft, a mathematical relationship results between the eccentricity e and the angular position of the eccentric shaft with regard to the axis of the arresting pin so that each adjusted eccentricity corresponds to a certain angular position of the shaft. The shaft angle corresponding to a selected eccentricity may -be calculated in advance and tabulated for the proper and easy adjustment of the desired eccentricity.

In order to avoid a scale with nonuniform graduations, the arrangement includes a scale divided in degrees arranged concentrically with respect to the axis of the shaft for rotation therewith, whereas a fixed mark is provided on the means mounting the shaft for rotation about its axis which cooperates with the zero mark of the scale. Preferably, a focusing microscope is provided which has an occular scale having a zero point coinciding with the aforementioned fixed mark. The focusing microscope is carried by the mounting means in such a manner that the scale provided on the shaft is visible through the microscope. The fixed mark on the mounting means and the zero mark of the scale connected to the eccentric shaft are preferably arranged with respect to each other in such a manner that when the sleeve is turned with respect to the shaft so that the eccentricity vectors of the eccentric shaft portion and the eccentric bore in the sleeve are superimposed upon each other, so that the two eccentricities will cancel each other, the zero mark of the scale will coincide with the fixed mark on the mounting means. In this adjusted zero position the radial groove on the sleeve will also extend in direction of the superimposed eccentricity vectors, that is in this zero position of the eccentric the eccentricity vector of the eccentric portion of the shaft will point away from the axis of the arresting pin Whereas the eccentricity vector of the bore in the sleeve will point toward the axis of the arresting pin. While it is also possible to select another Zero adjustment of. the system, the above-mentioned zero position provides for a simple solution of the mathematical relationship between the adjusted eccentricity and the angular position of the shaft. With the arrangement of the present invention it is possible to adjust the eccentricity of the eccentric with a tolerance of a few microns.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings in which:

FIG. 1 is a schematic axial cross section through the arrangement according to the present invention;

FIG. 2 is a schematic view illustrating the positions of the various elements of the arrangement in one adjusted position of eccentricity thereof; and

FIG. 3 is a schematic view similar to FIG. 2 and showing the elements in zero position.

Referring now to the drawings and more specifically to FIG. 1, it will be seen that the eccentric and the means for adjusting the eccentricity thereof according to the present invention mainly comprises a shaft 1 having an axis 1a and a cylindrical portion 2 fixed to the shaft 1, by being for instance integrally made with the same, and eccentrically arranged with respect to the shaft axis. The axis 2a of the cylindrical portion 2 extends parallel to the axis 1a of the shaft 1 and is spaced therefrom by the eccentricity e The shaft 1 is turnably mounted on opposite end portions thereof in mounting means 9 which may, as for instance shown in FIG. 1, be in the form of a housing. A drive gear 14 may be mounted for instance on the left end portion of the shaft extending beyond the housing 9, as viewed in FIG. 1, for rotation about the shaft and a coupling member 13 may be provided on the shaft end portion fixed to the shaft for rotation therewith, but movable in axial direction between the active position engaging the wheel 14 so that the latter during its rotation will drive the shaft about its axis and an inactive position in which the coupling member 13 is disengaged from the gear 14.

A sleeve 3 having an outer cylindrical surface 3' having an axis 3a is formed with an eccentric cylindrical bore 3" having a radius r (FIG. 2) which is equal to the radius of the eccentric cylindrical portion 2 on the shaft 1. The eccentric cylindrical portion 2 of the shaft 1 is arranged in the bore 3" of the sleeve 3. The eccentricity of the bore 3" with regard to the axis of the outer cylindrical surface of the sleeve 3 is, as indicated in FIG. 2, equal to the eccentricity 2 between the cylindrical portion 2 of the shaft and the shaft axis. An annular end 15 of a power takeoff member is arranged about the outer surface of the sleeve 3. A cylindrical portion 16 is arranged to the right side, as viewed in FIG. 1, of the eccentric cylindrical portion 2 of the shaft 1 and the cylindrical portion 16 is arranged coaxially with the axis 2a. A coupling member 10 provided with a frusto-conical end portion 10a is axially movable on the cylindrical portion 16 while being constrained to turn therewith and the frusto-conical portion 10a of the coupling member 10 cooperates with a corresponding frusto-conical cavity 10b provided in an enlarged wide end portion of the sleeve 3 in such a manner that when the frusto-conical end portion 10a is pressed into the frusto-conical cavity 10b, the sleeve 3 is connected to the shaft 1 for rotation therewith, whereas when the frusto-conical portion 10a is disengaged from the cavity 10b the sleeve may be turned with respect to the shaft 1. The coupling member 10 may be moved in axial direction between an engaged and a disengaged position by means of a lever 12 turnably mounted intermediate its ends on the housing 9, as shown in FIG. 1, and engaging with a spherical end into an annular groove 11 provided at the right end of the coupling member. The groove 11 has such a depth that the end of the lever 12 will not interfere with free rotation of the coupling member 10 together with the shaft 1. The lever 12 extends through an opening in the housing 9 to the outside of the latter so as to be operable from the outside of the housing. The sleeve 3 is further provided at the right end face thereof, as viewed in FIG. 1, with a radial groove R into which the knife edge A of an arresting pin may engage. The arresting pin 20 is mounted in an insert member 17 of the housing for movement in axial direction and turnably about its axis. The arrangement includes further a circular disk 21 fixed outside of the housing to the shaft 1 and provided with a scale 4, as will be explained later on in detail, arranged coaxial with the axis of the shaft. A focusing microscope 6 mounted on an arm 19 on the insert 17 is arranged in such a manner that the scale 4 on the disk 21 may be observed through the microscope 6. The right end of the shaft 1, as viewed in FIG. 1, is preferably square, as at 18, to facilitate turning of the shaft 1 about its axis during adjustment of the eccentricity of the eccentric.

FIG. 2 schematically illustrates at an enlarged scale the relative position of the various above-described eccentric parts with respect to each other and the angular relationship thereof during adjustment of a preselected eccentricity. The intersection point of the axis 1a of the eccentric shaft 1 with a plane normal to the eccentric shaft is designated in FIG. 2 with M, whereas the intersection point of the axis of the eccentric portion 2 on the shaft with the aforementioned plane is designated With B, the shaft turns therefore about the point M and the eccentricity of the eccentric portion 2 of the shaft e is equal to the vector MB. The point B is also the center point of the eccentric bore 3" with the radius r of the eccentric sleeve 3 having a radius r and an eccentricity e equal to the vector BC and equal to the eccentricity of the eccentric portion 2 of the shaft 1. The intersection of the axis of the arresting pin 20 with the plane normal to the shaft axis is indicated with A in FIG. 2 and the point A is spaced a distance h from the center point M of the shaft 1. When the arresting pin 20 is engaged in the radial groove B indicated in heavy dash-dotted lines in FIG. 2, on the right end face of the sleeve 3, as viewed in FIG. 1, the vector BC is directed toward the fixed point A as is evident from FIG. 2. The radial groove R is thereby arranged on the end face of the sleeve 3 in such a manner that the groove R is closer to the point C than to the point B.

In order to adjust a desired eccentricity e the coupling 13 is first disengaged from the gear 14 so that the shaft 1 can be manually turned by means of the square end portion 18. The shaft is turned until the arresting pin 20 is aligned with the radial groove R in the sleeve 3 and the arresting pin is then moved inwardly to engage into the radial groove. After this engagement, the sleeve 3 can make only radial movements with regard to the fixed point A and tilt about this fixed point, whereby the radial groove R will include an angle 7 with the zero line MA. The coupling portions 10a and 1012 are then disengaged from each other and the shaft turned about its axis relative to the arrested sleeve. During turning of the vector MB the angle a between this vector and the zero line MA and the angle [3 included between the vector MB and the vector BC will be changed. The angle a can also be read on the scale 4 provided on the disk 21 between the zero mark on the scale and a fixed mark 5 on the occular scale 7 of the focusing microscope 6 which is arranged in a fixed position on the housing 9. The zero point on the scale 7 provided on the disk 21 which turns with the shaft 1 and the fixed mark 5 on the occular scale 7 of the microscope 6 are arranged with respect to each other in such a manner that the zero mark on the scale 4 coincides with the fixed mark 5 on the occular scale of the microscope when the shaft 1 is turned relative to the arrested sleeve 3 to a position in which the eccentricity vector MB of the eccentric shaft portion 2 is superimposed upon the eccentricity vector BC as shown in FIG. 3, that is when the two eccentricity vectors cancel each other. In this zero position as shown in FIG. 3 the vector MB points away from the fixed point A and the vector BC points toward the fixed point A. From this zero position as shown in FIG. 3, the shaft 1 may be turned to any desired position which is readable on the scale 4 whereby the desired eccentricity can be read on this scale.

The relationship between the desired eccentricity 2 and the angle a readable on the scale 4 is established by the following formulas:

From the above formula it is possible to figure out from the fixed dimensions e and It of the arrangement the angles a corresponding to any desired adjusted eccentricity e The angles a corresponding to the respective desired eccentricity e are tabulated so that the arrangement may be easily adjusted for any desired eccentricity in the aforementioned manner and by relocking the sleeve 3 with respect to the shaft 1 after these two members have been adjusted with respect to each other in the aforementioned manner.

The eccentric arrangement above described may be used for instance for moving the grinding wheel of a polygon grinding machine whereby the feed movement of the grinding wheel is derived from the annular member 15 of the above-described arrangement.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of eccentric and means for adjusting the eccentricity thereof differing from the types described above.

While the invention has been illustrated and described as embodied in an eccentric and means for adjusting the eccentricity thereof, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. An eccentric and means for adjusting the eccentricity thereof comprising, in combination, a shaft having an axis and a cylindrical portion fixed to the shaft and eccentrically arranged with regard to said shaft axis; a sleeve surrounding said eccentrical-ly arranged portion on said shaft and having an outer cylindrical surface and a bore having an inner cylindrical surface of a diameter substantially equal to that of said cylindrical eccentric portion of said shaft and engaging the latter, said bore being eccentrically arranged with respect to the outer cylindrical surface of said sleeve, said sleeve having an end face formed with a radial groove; mounting means mounting said shaft turnably about its axis; releasable coupling means for releasably connecting said sleeve and said shaft to each other; and arresting means carried by said mounting means and having a free end adapted to engage in said groove to prevent said sleeve to turn about the axis of its cylindrical outer surface while permitting said sleeve to move in the direction transverse to the axis thereof and to tilt about said arresting means whereby when said coupling means is released and said arresting means engaged in said groove the eccentricity of said eccentric may be adjusted by turning said shaft about its axis.

2. An eccentric and means for adjusting the eccentricity thereof as set forth in claim 1, and including scale means fixed to said shaft for turning therewith about the axis of said shaft, said scale means having a scale concentric with the shaft axis and being divided in degrees.

3. An eccentric and means for adjusting the eccen tricity thereof as set forth in claim 2, wherein said scalemeans has a zero mark and including a fixed mark on said mounting means cooperating with said scale means, said marks being arranged with respect to each other in such a manner that said zero mark coincides with said fixed mark when said shaft is turned with respect to said sleeve so that said eccentncity vectors are superimposed upon each other.

4. An eccentric and means for adjusting the eccentricity thereof as set forth in claim 3, and including a focusing microscope having an occular scale having a zero point coinciding with said fixed mark, said focusing microscope being mounted in fixed position on said mounting means in such a manner that said scale means are visible through said microscope.

5. An eccentric and means for adjusting the eccentricity thereof as set forth in claim 4, wherein said mounting means is in the form of a housing surrounding said eccentric shaft portion and said sleeve therein, said shaft extending with opposite ends thereof beyond said housing and being turnably mounted on said shaft portions, said housing having an end wall facing said end face of said sleeve and said arresting pin being mounted in said end wall substantially parallel to the axis of said shaft movable in axial direction and t-urnable about its axis.

6. An eccentric and means for adjusting the eccentricity thereof as set forth in claim 5, wherein said scale means is in the form of a disk mounted on a shaft portion outside said housing, and said microscope being mounted in said housing opposite a portion of said disk.

7. An eccentric and means for adjusting the eccentricity thereof as set forth in claim 1, wherein said mounting means is in the form of a housing surrounding said eccentric shaft portion and said sleeve thereon, said shaft extending with opposite ends thereof beyond said housing and being turnably mounted on said shaft portions.

8. An eccentric and means for adjusting the eccentricity thereof as set forth in claim 7, wherein said coupling means is in the form of a friction cone coupling having a male frusto-conical face and a corresponding female frusto-conical face, one of said faces being provided in an end portion of said sleeve and the other on a coupling member mounted on said shaft movable in axial direction of the latter, and including operating means connected to said coupling member for moving the same between an engaged position and a disengaged position, said operating means extending through an opening in said housing to the outside of the latter.

References Cited UNITED STATES PATENTS 2,834,223 5/1958 Strnad 74-571 FOREIGN PATENTS 43 5,424 9/ 1935 Great Britain.

MILTON KAUFMAN, Primary Examiner. 

1. AN ECCENTRIC AND MEANS FOR ADJUSTING THE ECCENTRICITY THEREOF COMPRISING, IN COMBINATION, A SHAFT HAVING AN AXIS AND A CYLINDRICAL PORTION FIXED TO THE SHAFT AND ECCENTRICALLY ARRANGED WITH REGARD TO SAID SHAFT AXIS; A SLEEVE SURROUNDING SAID ECCENTRICALLY ARRANGED PORTION ON SAID SHAFT AND HAVING AN OUTER CYLINDRICAL SURFACE AND A BORE HAVING AN INNER CYLINDRICAL SURFACE OF A DIAMETER SUBSTANTIALLY EQUAL TO THAT OF SAID CYLINDRICAL ECCENTRIC PORTION OF SAID SHAFT AND ENGAGING THE LATTER, SAID BORE BEING ECCENTRICALLY ARRANGED WITH RESPECT TO THE OUTER CYLINDRICAL SURFACE OF SAID SLEEVE, SAID SLEEVE HAVING AN END FACE FORMED WITH A RADIAL GROOVE; MOUNTING MEANS MOUNTING SAID SHAFT TURNABLY ABOUT ITS AXIS; RELEASABLE COUPLING MEANS FOR RELEASABLY CONNECTING SAID SLEEVE AND SAID SHAFT TO EACH OTHER; AND ARRESTING MEANS CARRIED BY SAID MOUNTING MEANS AND HAVING A FREE END ADAPTED TO ENGAGE IN SAID GROOVE TO PREVENT SAID SLEEVE TO TURN ABOUT THE AXIS OF ITS CYLINDRICAL OUTER SURFACE WHILE PERMITTING SAID SLEEVE TO MOVE IN THE DIRECTION TRANSVERSE TO THE AXIS THEREOF AND TO TILT ABOUT SAID ARRESTING MEANS WHEREBY WHEN SAID COUPLING MEANS IS RELEASED AND SAID ARRESTING MEANS ENGAGED IN SAID GROOVE THE ECCENTRICITY OF SAID ECCENTRIC MAY BE ADJUSTED BY TURNING SAID SHAFT ABOUT ITS AXIS. 